code: def test_forward(self):
      neck = FPEM(in_channels=8)
      neck.init_weights()
      out = neck(self.c2, self.c3, self.c4, self.c5)
      self.assertTrue(out[0].shape == self.c2.shape)
      self.assertTrue(out[1].shape == self.c3.shape)
      self.assertTrue(out[2].shape == self.c4.shape)
      self.assertTrue(out[3].shape == self.c5.shape)
  
file_path: mmocr/tests/test_models/test_textdet/test_necks/test_fpem_ffm.py
imports: import unittest
  import torch
  from mmocr.models.textdet.necks.fpem_ffm import FPEM, FPEM_FFM
label_desc: Use image node_id 2 for calling the TestFPEM obj's underlying member method code with example usage: obj.test_forward() without return types